Fluid sealing assembly for a marine riser telescopic slip joint

Abstract

A fluid sealing apparatus for use on telescopic slip joints of marine risers. A sealed housing is secured to one of the two telescopic members of the slip joint in a concentric surrounding relationship to the other tubular members with an annular recess disposed adjacent thereto. Positioned within the annular recess is one or more resiliently deformable packing elements operably deformed by sliding movement of an associated fluid pressure responsive packing follower. The packing follower is movable within the recess toward a central guide bushing for urging the packing disposed therebetween to be radially inwardly deformed for initially establishing and maintaining the desired fluid leakage blocking seal. The packing follower forms an enclosed annular expansible chamber within the sealing housing in order that a preselected quantity of hydraulic fluid introduced within the enclosed chamber will move the packing follower sufficiently to establish the initial or reference urging on the packing for operably deforming the packing sufficiently to effect and maintain the initial seal. The packing follower is also exposed to the pressure contained within the marine riser for feeding additional packing radially inwardly as the working pressure of the contained fluid increases and the packing wears. To enhance the useful operating life of the resilient packing a central movement guide bushing is preferably disposed between the companion sealing elements.

I claim: 
     
       1. A fluid sealing apparatus adapted for use in a slip joint of a marine riser, the slip joint having relative reciprocating inner and outer tubular members which form a portion of the contained fluid flow path provided by the marine riser and which telescopically move relative to the other member to compensate for variations in effective riser length, said fluid sealing apparatus, including: a seal housing adapted to be secured to one of the tubular members for operably positioning said seal housing relative to the other of the tubular members, said housing have an annular recess disposed adjacent the other of the tubular members;   a resiliently deformable packing disposed in said annular recess for forming a desired fluid seal between said seal housing and the other of the tubular members to prevent undesired leakage of fluid therebetween;   a packing follower movably disposed in said annular recess for urging said packing to operably deform to effect the desired fluid seal, said packing follower responsive to a prearranged fluid pressure urging thereon to urge said packing to operably deform for effecting the desired seal;   said seal housing concentrically surrounding the other tubular members for enabling relative movement therebetween when secured and to one of the tubular members to juxtapose said annular recess and the other tubular member;   said packing follower having substantially a sleeve shape for positioning in said annular recess while concentrically surrounding the other tubular member, said packing follower slidably disposed in said annular recess for movement to operably deform said packing;   said sleeve-shaped packing follower having an outer surface formed by a first constant diameter portion and a second constant diameter portion, said first diameter portion having a greater diameter than said second diameter portion;   a first seal means for slidably sealing said first constant diameter portion to said seal housing; and   second seal means for slidably sealing said second constant diameter portion to said seal housing, said first seal means and said second seal means partially defining an enclosed expansible chamber for urging said packing follower to operably deform said packing in response to the fluid pressure in said enclosed expansible chamber.   
     
     
       2. The fluid sealing apparatus as set forth in claim 1, wherein: said sleeve-shaped packing follower responsive to the fluid pressure contained in the marine riser for urging said packing follower to operably deform said packing in response to the fluid pressure in the marine riser.   
     
     
       3. A fluid sealing apparatus adapted for use in a slip joint of a marine riser, the slip joint having inner and outer tubular members which form a portion of the contained fluid flow path provided by the marine riser and which telescopically move to the other member to compensate for variations in effective riser length, said fluid sealing apparatus including: a seal housing adapted to be secured to one of the tubular members for operably positioning said seal housing relative to the other of the tubular members, said housing having an inner cylindrical surface forming an annular recess disposed adjacent the other of the tubular members;   a guide bushing releasably secured in said annular recess, said guide bushing having a cylindrical inner surface surrounding a cylindrical outer portion of the other tubular member for enabling and guiding sliding telescopic movement therebetween while maintaining a substantially concentric relationship;   a pair of resiliently deformable packings disposed in said annular recess, each of said packings forming a desired fluid seal between said seal housing and the other of the tubular members to prevent undesired leakage of fluid therebetween said guide bushing position between said packings;   each packing having a packing follower movably disposed in said annular recess for urging each of said packings toward said guide bushing to operably deform said packing to effect the desired fluid seal, said packing follower responsive to a prearranged fluid pressure urging thereon to urge said packing to operably deform for effecting the desired seal;   each said packing follower sealed to said seal housing to form an enclosed expansible chamber, each said packing follower having a first pressure responsive surface exposed to the fluid pressure in said enclosed expansible chamber for urging said packing follower toward said guide bushing to deform said packing in response to the fluid pressure in said enclosed expansible chamber for urging said packing follower toward said guide bushing to deform said packing in response to the fluid pressure in said enclosed chamber;   means formed in said housing for enabling introduction of a controlled amount of fluid into said enclosed expansible chamber to provide a predetermined urging on said packing follower toward said guide bushing to deform said packing sufficiently to establish a seal;   one of said packing followers having a second pressure responsive surface exposed to the fluid pressure contained within the marine riser for urging said packing follower toward said guide bushing to deform said packing in response to the fluid pressure in the marine riser wherein the fluid pressure urging on said first and said second pressure responsive surfaces of each packing follower urge said follower toward said guide bushing to deform said packing to maintain the desired seal;   each said packing follower having an outer surface formed by a first constant diameter portion and a second constant diameter portion, said first diameter portion having a greater diameter than said second diameter portion;   a first seal means for slidably sealing said first constant diameter portion to said seal housing; and   second seal means for slidably sealing said second constant diameter portion to said seal housing, said first seal means and said second seal means forming said first pressure responsive surface and partially forming said enclosed chamber for urging on said packing follower to operably deform said packing in response to the fluid pressure in said enclosed expansible chamber.   
     
     
       4. A fluid sealing apparatus adapted for use in a slip joint of a marine riser, the slip joint having inner and outer tubular members which form a portion of the contained fluid flow path provided by the marine riser and which telescopically move relative to the other member to compensate for variations in effective riser length, said fluid sealing apparatus including: a seal housing adapted to be secured to one of the tubular members for operably positioning said seal housing relative to the other of the tubular members, said housing having an inner cylindrical surface forming an annular recess disposed adjacent the other of the tubular members;   a guide bushing releasably secured in said annular recess, said guide bushing having a cylindrical inner surface surrounding a cylindrical outer portion of the other tubular member for enabling and guiding sliding telescopic movement therebetween while maintaining a substantially concentric relationship;   a resiliently deformable packing disposed in said annular chamber adjacent said guide bushing for forming a desired fluid seal between said seal housing and the other of the tubular members to prevent undesired leakage of fluid therebetween;   a packing follower movably disposed in said annular chamber for urging said packing toward said guide bushing to operably deform said packing to effect the desired fluid seal, said packing follower responsive to a prearranged fluid pressure urging thereon to urge said packing to operably deform for effecting the desired seal;   said packing follower having an outer surface formed by a first constant diameter portion and a second constant diameter portion; said first diameter portion having a greater diameter than said second diameter portion;   a first seal means for slidably sealing said first constant diameter portion to said seal housing; and   second seal means for slidably sealing said second constant diameter portion to said seal housing, said first seal means and said second seal means partially defining an enclosed expansible chamber for urging said packing follower to operably deform said packing in response to the fluid pressure in said enclosed expansible chamber.   
     
     
       5. The fluid sealing apparatus as set forth in claim 4, wherein: said packing follower responsive to the fluid pressure contained in the marine riser for urging said packing follower to operably deform said packing in response to the fluid pressure in the marine riser.